safety valve is a key safety component of boilers, pressure vessels and other pressurized equipment. Its reliability and performance are directly related to the safety of the equipment and operators, as well as to energy saving and environmental protection. If the set pressure of the safety valve is too high, it may not be able to open in time in dangerous situations, thus increasing the risk of accidents; while if the set pressure is too low, it may lead to leakage, which is not only a waste of energy, but also pollutes the environment, and even damages the sealing surface of the safety valve due to frequent opening.
The set pressure (also known as the opening pressure) of a safety valve is a crucial parameter that determines whether the safety valve will open in time when the equipment is subjected to excessive pressure. We usually calibrate safety valves once a year, mainly to check whether there is any internal damage, whether the sealing surface is intact, and to reset the opening pressure of the safety valve to ensure that it is in the best working condition.
Now that we understand the importance of safety valve set pressure, how to calculate the set pressure of the safety valve? The following is an example of the calculation method for steam boilers and pressure vessels.
For steam boiler safety valve setting value:
When the rated steam pressure is less than or equal to 0.8MPa, the set pressure of the two safety valves are the working pressure plus 0.03MPa and 0.05MPa.
When the rated steam pressure is between 0.8MPa and 5.9MPa, the set pressures of the two safety valves are 1.04 and 1.06 times the working pressure respectively.
When the rated steam pressure is greater than 5.9MPa, the set pressures of the two safety valves are 1.05 and 1.08 times the working pressure respectively.
It should be noted that there must be at least one safety valve on the boiler adjusted to the lower setting pressure mentioned above. Also, the working pressure here refers to the working pressure at the location where the safety valve is installed. For economizers and reheaters, the set pressure of the safety valve is 1.1 times the working pressure at the installation position.
For pressure vessels the set pressure of the safety valve:
If only one safety valve is installed, its opening pressure should not be greater than the design pressure and the sealing test pressure should be greater than the maximum working pressure of the vessel. Specifically, the maximum working pressure is less than the opening pressure, while the opening pressure should not exceed the design maximum working pressure (the opening pressure is usually 1.05-1.1 times the maximum working pressure).
Setting the parameters of the safety valve is a very rigorous work, selecting the appropriate set pressure parameters will directly affect the safety of the equipment. Here, we provide the above calculation method for your study and exchange to ensure that we work together in a safe environment.
Translated with DeepL.com (free version)
